1. Field of the Invention
The present invention relates to multi-start spiral separators adapted for separating particles in a stream of such particles according to their respective densities and/or sizes.
2. Description Of The Prior Art
Conventionally a spiral separator consists of a plurality of helical troughs arranged in a column around a supporting central pillar. The troughs are arranged after the fashion of the threads of a multi-start screw. A column may consist of as many as ten separate troughs each trough being fed at its upper end from an individual slurry feed pipe, by means of which a slurry, such as a slurry of fine coal particles, is fed into the trough. Where a small number of troughs is present in the column this arrangement is satisfactory. However, as the number of troughs increases the arrangement of feed pipes becomes increasingly complicated and cumbersome.